Defroster



p 1938- J. A. SHRADER 2,130,036

DEFROSTER Filed July 21, 1934 INVENTOR BY w y 1 ATTOR N EY PatentedSept. 13, 1938 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to a defroster for a refrigerator or similardevice of the character having a cooling orfreezing unit and has for theprimary object the provision of means for direct- 5 ing a blast of aironto .the cooling or freezing unit' at any selected period of time tobring about a thorough or rapid defrosting for removal of the snow orice on the cooling or freezing unit and which may take place while therefrigerator or 10 similar device is closed to the atmosphere whichpermits the refrigerator to remain at a low or lower temperature thanheretofore accomplished through the ordinary way of defrosting.

With these and other objects in view this invention consists incertainnovel features of construction, combination and arrangement ofparts to be hereinafter more fully described and claimed.

For a complete understanding of my invention,

20 reference is to be had to the following description and accompanyingdrawing, in which Figure 1 is a fragmentary view showing my inventionapplied to a cooling or freezing unit of a refrigerator or similardevice.

25 Figure 2 is a diagrammatical view illustrating the wiring diagramwith my invention electrically connected thereto.

Referring in detail to the drawing, the numeral I indicates a cooling orfreezing unit of the con- 30 ventional construction adapted for cooling2. re-

frigerator or like device 2. To maintain the unit 8 at its highest pointof efficiency it is necessary to defrost or remove from the unit theaccumulation of snow ,or ice which is usually accom- 35 plished byrendering the device inoperative for a period of time to permit the snowand ice to melt fromsaid unit. Usually the defrosting operation requiresa number of hours in which time the interior of the refrigerator or likedevice rises in temperature and to reduce the length of time to defrostthe unit and to maintain the refrigerator at a comparatively lowtemperature my invention is employed which consists of a medium 3 todirect a blast of air onto the cooling or freeztively low temperature.The medium 3 is in the form of an electric motor 4 having secured to thearmature shaft thereof a fan 5. The motor 4 may be'located within anydesired place in the refrigerator so that the fan 5 when in operation 5can direct air against the freezing or cooling unit I. Figure 2 showsthe wiring 6 of an electrically actuated circuit for the unit I andwhich circuit is opened and closed by a temperature control "I. Thetemperature control is in the nature of a bellows-like member which isexpanded or contracted by temperature conditions. The electric motor 4is connected to the electric circuit 6 by conductors 8, 9 and Hi. Theconductors 8 and 9 are separated by spaced contacts ll. Pivoted to thetop of the temperature control I there is one end of a. lever l2, thatis centrally pivoted to a supporting standard l3. The outer or free endof the lever has arranged therearound but insulated therefrom a U-shapedcontact plate I4. Subjacent the contact plate l4 there is positioned apair of spaced contacts l5 each connected to one of the pair'of maincircuit wires 6 leading to the compressor motor for the unit I.Thecontact plate I4 is movable by the lever I2 to bridge the spacedcontacts I l to direct current from the main circuit to the fan motor 8and break the connection between the contacts 15 to shut off currentfrom said main circuit to the compressor motor for unit I, or viceversa, in accordance with the expansion or contraction of the controlelement 1. Thus it will be seen that the electric motor 4 is set inoperation when the motor of the refrigerant unit is stopped. Thisarrangement ormeans for directing air onto the cooling coil when thecompressor is idle will materially aid in preventing the accumulation offrost and snow thereon thereby practically keeping the cooling unit in adefrosted condition over a long period of time.

Having described the invention, I claim:

The combination with a refrigerating system including its evaporator,compressor and driving motor therefor, of an independent motor drivenfan for causing a flow of air through the refrigerator evaporator, and athermostat controlling the refrigerating system compressor motor and fandriving motor for alternate operations JOHN A. SHRADER.

